What makes a mycoparasite? Similarities between fungi that attack other fungi and fungal and oomycete plant pathogens based on structural homology of their candidate effectors

The paper is situated within mycology and microbial ecology. The prevailing paradigm for understanding mycoparasitism (fungi parasitizing other fungi) has been largely descriptive, relying on empirical observation and ecological classification. This research introduces a new conceptual model by framing mycoparasitism within the well-established molecular paradigm of plant-pathogen interactions. It proposes that, like plant pathogens, mycoparasites utilize secreted effector proteins to manipulate their fungal hosts, thus shifting the explanatory framework from ecological description to molecular mechanisms.

This preprint initiates a Model Revolution by proposing a novel hypothesis that fundamentally reframes how mycoparasitism is understood. It moves beyond the existing descriptive paradigm by suggesting the molecular mechanisms are analogous to those in plant-pathogen systems. The key finding—that candidate effector proteins from diverse mycoparasites are structurally homologous to effectors from a model plant pathogen—provides strong evidence for this new conceptual model. This is not an incremental addition but a new way of seeing the problem, offering a powerful mechanistic framework to guide future research in a field previously lacking one.